1. Field of the Invention
The invention concerns mixer taps for mixing two incoming flows of fluids at different temperatures to constitute a single outgoing flow of fluid at a constant temperature that can be varied independently of the respective pressures and temperatures of the two incoming flows of fluid and of the flowrate of the outgoing fluid within a particular range of pressures and flowrates.
It is more particularly concerned with the construction of a cartridge fitted inside such mixer taps, in particular controlling a mobile regulator slide that adjusts the incoming fluid flows in accordance with the required outgoing fluid temperature.
2. Description of the Prior Art
In mixer taps known per se intended in particular for sanitary installations (showers, baths with or without showers, etc), to obtain the most stable possible and precise regulation the travel of the regulator slide rarely exceeds one millimeter for a (conventional) adjustment range from 20.degree. C. to 60.degree. C. As a result a variation of 1.degree. C. is produced by a travel of 0.025 mm, which enables great accuracy and a reliable setting within the comfortable range from 35.degree. C. to 40.degree. C. (corresponding to a travel of 0.125 mm). However, the required accuracy and reliability, together with good temperature stability, are obtained at the cost of accurate guidance of the slide.
What is more, to conform to safety standards, an interruption in the cold water supply must cut off the hot water supply, only extremely low leakage being tolerated. The slide must therefore be able to position itself freely on its seat.
The guidance needed to obtain accuracy, reliability and stability, which constitutes an impediment to free positioning of the slide on its seat, is therefore a disadvantage from the point of view of safe operation of the mixer tap.
What is more, the hot water supply must be cut off extremely quickly. The reaction speed of the assembly depends on the one hand on that of the thermostats used in this type of application, usually wax-based and open to improvement, and on the other hand on that of the intimate mixing of the incoming flows of water, which is also open to improvement. The invention aims to achieve a reaction time of less than one second when the cold water supply is cut off.
It is also necessary for the cartridge to be easy and quick to fit into the body of the mixer tap, which is not always the case in mixer taps known per se.